NumPy: Replace all numbers in a given array which is equal, less and greater to a given number

NumPy: Basic Exercise-54 with Solution

Write a NumPy program to replace all numbers in a given array equal, less and greater than a given number.

Sample Solution:

Python Code :

# Importing the NumPy library with an alias 'np'
import numpy as np

# Creating a NumPy array 'nums' containing values in a 3x3 matrix
nums = np.array([[5.54, 3.38, 7.99],
              [3.54, 8.32, 6.99],
              [1.54, 2.39, 9.29]])

# Printing a message indicating the original array
print("Original array:")
print(nums)

# Assigning values to variables 'n' and 'r'
n = 8.32
r = 18.32

# Printing a message indicating the replacement of elements equal to 'n' with 'r'
print("\nReplace elements of the said array which are equal to", n, "with", r)
print(np.where(nums == n, r, nums))

# Printing a message indicating the replacement of elements less than 'n' with 'r'
print("\nReplace elements of the said array which are less than", n, "with", r)
print(np.where(nums < n, r, nums))

# Printing a message indicating the replacement of elements greater than 'n' with 'r'
print("\nReplace elements of the said array which are greater than", n, "with", r)
print(np.where(nums > n, r, nums)) 

Sample Output:

Original array:
[[5.54 3.38 7.99]
 [3.54 8.32 6.99]
 [1.54 2.39 9.29]]

Replace elements of the said array which are equal to  8.32 with 18.32
[[ 5.54  3.38  7.99]
 [ 3.54 18.32  6.99]
 [ 1.54  2.39  9.29]]

Replace elements with of the said array which are less than 8.32 with 18.32
[[18.32 18.32 18.32]
 [18.32  8.32 18.32]
 [18.32 18.32  9.29]]

Replace elements with of the said array which are greater than 8.32 with 18.32
[[ 5.54  3.38  7.99]
 [ 3.54  8.32  6.99]
 [ 1.54  2.39 18.32]]

Explanation:

In the above code –

np.array(...): Creates a 3x3 NumPy array with the given values and stores in a variable ‘nums’.

n = 8.32 and r = 18.32: Set the variables n and r to 8.32 and 18.32, respectively.

np.where(nums == n, r, nums): This statement uses np.where() to create a new array with the same shape as nums. For each element in nums, if the element is equal to n (8.32), the new array will have the value r (18.32) at the corresponding position; otherwise, the new array will have the same value as in nums.

Python-Numpy Code Editor:

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